Srock.—On the Longitude of Wellington Observatory. 219 
the former value is more likely to be true than the latter, for these reasons: 
I sent the signals from Wellington, and the evidence of all in the Obser- 
vatory was that the key was pressed down synchronously with the fifteenth- 
second beats of the clock. The signals from Sydney were received by an 
assistant, whose cry at the movement of the flash, as the Sydney key was 
pressed down, was compared by me with the clock beats. "Thus the second 
process passed through two observers. It is also vastly more difficult to 
receive than to send. It may be certainly presumed also that the Sydney 
observers were more practised in the work than those at Wellington, to 
whom the work was new. But the difference thus gained thoroughly 
establishes that obtained by the chronometers of the “ Acheron " and 
* Pandora." 
* 
| Fort Macquarrie Pipitea Point} 
1h. 34m. 155338. 
| Sydney Observatory, 2°63 E. of Fort M. Wellington Observatory, 2'88 W. of P. Pej 
. 34m. 15:9949s. 
The difference between the two values is only half a second; and if, as I 
think should be done, that value be allowed for superiority of the signals 
from Wellington to Sydney to those of the reverse way the two values will 
be nearly identical. 
The value now given for the longitude of Sydney Observatory is 10h. 04m. 
47:82s. This new value would give for that of Wellington Observatory 
11h. 39m. 02-6s. 
The value of Sydney Observatory, however, as gained from the Obser- 
vatory of Melbourne is 10h. 04m. 50°61. This value gives for Wellington 
Observatory 11h. 39m. 05:898s.* 
Major Palmer's value, gained by comparison of time difference between 
Wellington and Burnham (Burnham longitude being fixed after several 
mouths’ observation), is 11h. 89m. 4:81s.t 
These longitudes are therefore :— 
RC € Wellington from Sydney, with old value of 
,1.—11 89 09°18 | Sydney Observatory. 
Wellington from Sydney and Melbourn 
2.—11 89 05:893 | RESE A iod d 
8.—11 89 0481 Wellington from Burnham. 
4.—11 389 02:6 Wellington from Sydney, new value. 
Confessedly no problem is more difficult than that of obtaining an 
absolute longitude by observation. Even with the instruments at the Royal 
* Hector, ** Trans. N.Z. Inst.," Vol. VII., p. 504. 
t New Zealand Gazette, 30th March, 1876. 
